Detection of particles with a cloud chamber

Cloud chambers were essential devices in early nuclear and particle physics research. Superseded by more modern detectors in actual research, they still remain very interesting pedagogical apparatus. This thesis attempts to give a global view on this topic. To do so, a review of the physical foundations of the diffusion cloud chamber, in which an alcohol is supersaturated by cooling it with a thermal reservoir, is carried out. Its main results are then applied to analyse the working conditions inside the chamber. The analysis remarks the importance of using an appropriate alcohol, such as isopropanol, as well as a strong cooling system, which for isopropanol needs to reach −40ºC. That theoretical study is complemented with experimental tests that were performed with what is the usual design of a home-made cloud chamber. An effective setup is established, which highlights details such as a grazing illumination, a direct contact with the cooling reservoir through a wide metal plate, or the importance of avoiding vapour removal. Apart from that, video results of different phenomena that cloud chamber allow to observe are also presented. Overall, it is aimed to present a physical insight that pedagogical papers usually lack.

Um estudo da quebra espontânea de simetria usando quartetos BRST

A Quebra Espontânea de Simetria (QES) tem sido discutida em muitos cenários, tendo resultados importantes na física Teórica de Partículas, sendo motivo de extensa pesquisa e com variadas aplicações. Neste trabalho, será apresentado um modelo alternativo baseado na Ação de Fujikawa usando quartetos BRST. No primeiro capítulo, todo o ferramental para a análise da QES é discutido partindo da definição em nível clássico e por fim no regime quântico, usando o conceito de ação efetiva. A técnica de quantização de campos de calibre no U(1), presente no eletromagnetismo, foi abordada, usando o cálculo dos propagadores e seus respectivos diagramas de Feynman. Foi estudado em conjunto com esse assunto, o conceito de campos fantasmas de Fadeev-Popov e Simetria-BRST. O mecanismo de Higgs é explorado em nível quântico, sendo feita um estudo dos rearranjos dos graus de liberdade do sistema. No segundo capítulo, as propriedades dos quartetos-BRST são estudadas, bem como suas considerações sobre simetria, quando aplicadas na ação de Fujikawa usando dois cenários: (i) quando a simetria não é quebrada. (ii) A simetria é quebrada. E por fim é feita uma análise sobre os graus de liberdade do sistema.

El ordenador y las nuevas tecnologías en el proceso de enseñanza universitaria.

Hemos consolidado la experiencia de la utilización de programas de cálculo simbólico y otros medios de generación de información como vehículos de transmisión de conocimientos muy útiles en el proceso de enseñanza universitaria. Se ha utilizado Internet como medio para poner a disposición de los alumnos materiales relativos a las diferentes asignaturas de la Licenciatura de Ciencias Físicas que permiten a los alumnos un mejor aprendizaje y profundización en sus conocimientos. Se ha introducido en el aula el uso del ordenador y cañón de proyección que permite una mayor agilidad y flexibilidad en las transmisión de los conocimientos que ha resultado ser una metodología alternativa que, de acuerdo con la experiencia obtenida, ha mejorado de forma notable la motivación del alumno, su rendimiento académico y formación. Basándonos en los resultados obtenidos y la experiencia acumulada, hemos puesto en marcha, en el curso 2001-02, una asignatura de libre configuración dedicada al cálculo simbólico que ha tenido una excelente acogida entre el alumnado de la Universidad de Valladolid.

XVI Reunión de la Conferencia General de la Unesco.

Se destacan párrafos de las intervenciones realizadas por algunos representantes de los países invitados. Se hace un resumen del programa aprobado para próximo bienio que centrará sus actividades en materia de educación en la democratización de la enseñanza y la educación permanente. En las ciencias exactas y naturales inauguración de un programa a largo plazo sobre el hombre y la biosfera, asimismo estimulará la cooperación internacional en la investigación en física teórica, ciencias de la información y biología. En materia de ciencias sociales tratará al desarrollo, al fomento de los derechos humanos y a la paz. En cultura conservación y valorización de lugares de interés histórico y turístico. La Conferencia aprobó una Convención sobre las medidas que deben adoptarse para prohibir e impedir la importación, exportación y la transferencia de propiedad ilícita de bienes culturales. Se finaliza con el texto de las conclusiones del debate general.

Elaboración del Plan de Estudios en Óptica y Optometría de la Universidad de Valladolid de acuerdo a los principios de convergencia europea.

Resumen tomado de la publicación

Implementação da técnica de difração de elétrons de baixa energia

The purpose of this study is to describe the implementation of the Low Energy Electron Diffaction (LEED) technique in the Laboratory of Magnetic Nanostructures and Semiconductors of the Department of Theoretical and Experimental Physics of the Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil. During this work experimental apparatus were implemented for a complete LEED set-up. A new vacuum system was also set up. This was composed of a mechanical pump, turbomolecular pump and ionic pump for ultra-high vacuum and their respective pressure measurement sensors (Pirani gauge for low vacuum measures and the wide range gauge -WRG); ion cannon maintenance, which is basically mini-sputtering, whose function is sample cleaning; and set-up, maintenance and handling of the quadrupole mass spectrometer, whose main purpose is to investigate gas contamination inside the ultra-high vacuum chamber. It should be pointed out that the main contribution of this Master's thesis was the set-up of the sample heating system; that is, a new sample holder. In addition to the function of sample holder and heater, it was necessary to implement the function of sustaining the ultra-high vacuum environment. This set of actions is essential for the complete functioning of the LEED technique

Estudos de sinterização da mistura de pós cerâmicos diatomita-titânia

This work is part of an effort of consolidation of a daily search for powder technology at the Department of Physics of the Universidade Federal do Rio Grande do Norte. This work objective the study and development of new ceramic materials from raw materials abundant at the region. For this, were studied ceramic mixtures of powders from diatomite-titania to aiming at a new ceramic material from powder technology. The experimental work involved a characterization of ceramic powders from a diatomite-titania mixture. The powders obtained were pressed and then parameters like variation of mass, linear shrinkage, activation energy and the mechanism of sintering are studied in function of the time and temperature of sintering, beyond microstructural analysis. The obtained results allow us estimate the optimizing of sintering conditions of this material

Montagem e construção de um magnetômetro a efeito Kerr magneto-óptico

n this master s dissertation a Kerr Magneto Optic s magnetometer effect was set up to do characterization of samples type films fine and ultra thin, these samples will be grown after the implementation of the sputtering technique at the magnetism laboratory of of this department. In this work a cooled electromagnet was also built the water and that it reaches close values to 10kOe with a gap of 22 mm including an area of uniform field of 25mm of diameter. The first chapter treats of the construction of this electromagnet from its dimensioning to the operation tests that involve measures of reached maximum field and temperature of the reels when operated during one hour. The second chapter is dedicated to the revision of the magnetism and the magnetization processes as well as it presents a theoretical base regarding the magnetic energies found in films and magnetic multilayer. In the sequence, the third chapter, is especially dedicated the description of the effects magneto opticians the effect kerr in the longitudinal, traverse and polar configurations, using for so much only the classic approach of the electromagnetism and the coefficients of Fresnel. Distinguished the two areas of observation of the effect regarding thickness of the film. The constructive aspects of the experimental apparatus as well as the details of its operation are explained at the room surrender, also presenting the preliminary results of the measures made in one serializes of permalloy films and concluding with the results of the characterization of the first films of iron and permalloy grown here at the theoretical and experimental physics department at UFRN

Modelagem estocástica de opções de câmbio no Brasil: aplicação de transformada rápida de Fourier e expansão assintótica ao modelo de Heston

Pós-graduação em Física - IFT

Equações diferenciais com retardo em biologia de populações: Renato Mendes Coutinho. -

Pós-graduação em Física - IFT

Superfluido de fermi aprisionado com Variação de Interação Atômica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Energia escura acoplada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Equações de estado exóticas na equação de Einstein

Pós-graduação em Física - IFT

Can entanglement explain black hole entropy?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estabilidade de sistemas condensados com interação atrativa ou repulsiva

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)